ST X-NUCLEO-SRC1M1, Руководство пользователя

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• the recovery word is mandatory to get back to an operational system. Recovery words are:
–
0x18 written on the I2C register 0 to return to the normal mode;
– 0x28 written on the I2C register 0 to return to the low-power mode;
– 0x08 written on I2C register 0 to return to the hibernate mode.
The recovery word erases the error register (register 2) but does not connect the consumer or the provider path to
V
BUS
nor V
CONN
. Write the corresponding bits to close one or more switches on the additional step.
1.2.9 CC line overvoltage protection
Unplugging a defective cable, with a voltage higher than 5 V, from the USB Type-C™ connector might cause
a V
BUS
short to the CC lines (adjacent lines). This also might apply a voltage higher than the one specified for
the STM32 AMR on the CC lines (FT IO). The TCPP02-M18 overvoltage protection on the CC lines protects the
STM32.
1.2.10 LDO
The ST715PU33R (U2) is a 3.3 V high input voltage LDO, supplied through the provider path (for example, CN3).
To supply the system with the LDO output, you must close JP1 with:
•
a jumper between 1 and 2 to connect the 3.3 V output voltage to the 3.3 V of the system;
• a jumper between 3 and 4 to force the STM32 NRST pin to 3.3 V (otherwise it might cause a potential
parasitic reset).
The D6 green LED signals the 3.3 V presence on the X-NUCLEO-SRC1M1 .
Figure 12. LDO configuration
3. 3 V
High input voltage
85 mA LDO linear regulator
GND GND
3.3V
NRST
U2 ST715PU33R
IN
1
9
Exp Pad GND
OUT
8
NC1
2
NC2
3
GND
4
NC3
7
NC4
6
FB
5
JP1
TSW-102-07-F-D
1 2
3 4
R23
1k
D8
LED green
C6
470n 5V
1
2
C5
100n 25V
1
2
Provider
GND
SOURCE
R22
4k
D7
LED5 blue
1.2.11 TCPP02-M18 overview
3.3 V is connected to the VCC/VCONN pin of the TCPP02-M18 (U1). It supplies the IC and also provides the
input voltage for V
CONN
.
V
CONN
voltage can be in the range of 3.0 to 5.5 V according to the USB-PD standard: VCC/VCONN is compatible
with this voltage range.
All
TCPP02-M18 I/Os connected to the STM32 are compliant with 3.3 V and 1.8 V (FLGn, ENABLE, IANA, SDA,
SLC), except CC1 and CC2 I/Os, in which they are in accordance with the USB-PD standard voltages. I2C_ADD
is also compliant with 3.3 V and 1.8 V.
The
TCPP02-M18 ENABLE pin is connected to the STM32 GPIO but you can also connect it directly to 3.3 V with
the R29 resistor.
The CBIAS pin capacitor (C3) is the
TCPP02-M18 ESD capacitor. Its value must be ≥100 nF and 50 V rated to
limit the voltage derating.
UM2973
Hardware architecture
UM2973 - Rev 1
page 10/25